Described herein is a pull mat for tunnel composting.
Pull mats are used in tunnel composting where compostable material is being composted while being placed on a pull mat. The pull mat is used to pull compost out of the composting tunnel.
Composting companies use composting tunnels wherein a substrate for mushroom culture can be produced, for example from a mixture of straw, horse manure, chicken manure and gypsum. This composting process requires three consecutive phases wherein the processing conditions in each phase are controlled. The floor of the tunnel comprises a grid through which air can be blown into the compostable material.
After each of the composting phases the compost is pulled out of the composting tunnel so that the compostable material may be mixed. The composting material may be humidified and/or spawn may be added to the compost. The pull mat is subsequently used to get the compostable material out of the composting tunnel.
The pull mat slides over so-called gliding mat which is attached to the grid in the floor of the composting tunnel. The gliding mat is applied to lower the friction as compared to direct contact of the pull mat with the grid in the floor of the composting tunnel.
A pull mat has to combine high resistance against elongation and rupture to enable easy removal of compostable material from the tunnel with highest possible air permeability to facilitate the composting process.
A pull mat preferably also minimizes friction in contact with the gliding mat.
U.S. Pat. No. 7,501,360 B2, BE 1016731 A3 and NL 1026898 C all disclose a pull mat for tunnel composting comprising a fabric of warp and weft threads having at least one strip in longitudinal direction, which has higher tensile strength and lower stretch than the areas of the fabric adjacent to at least one the strip.
NL 1034567 C discloses a composting mat comprising a woven fabric of the ajour type wherein warp and weft threads are grouped together.